2 & 4 channel audio?

[Matt Trecartin]

My company just bought 2 350's with Cannon KH10ex3.6 glass for documentary production.

We do all of our shooting in HD (HQ) res.

We noticed that you can only record 4 channels of audio in 60i mode. We switched to 30p mode to run some tests and had no audio at all until we changed the number of channel inputs to 2.

Are we doing something wrong? Or is this just the way it is?

Just thought I'd pass this along as it was somewhat frustrating to figure out why the mic wasn't working.

Matt Trecartin
Director / DOP
Arcadia Entertainment Inc.

www.arcadiatv.com
www.marinemachines.com

[Greg Boston]

Something doesn't sound right. I can't tell exactly from your description exactly what was happening.

We noticed that you can only record 4 channels of audio in 60i mode...

You should be able to choose 2ch or 4ch in 60i. Just keep in mind that whatever you choose, when you put a fresh disc in the camera, the disc will get formatted to that setting. You can't change the number of audio channels in the middle of a disc. You have to re-format, or use a fresh disc. Same goes for 23.98.

You can, however, mix 60i and 30P on the same disc, but the number of audio channels must remain constant. Other than that, check your input switches for ch1 and ch2 to make sure they are set for front if using the front mic connector.

-gb-

[Matt Trecartin]

yeah sorry, I wasn't very clear.

We can of course record either 2 or 4 channels of audio in 60i mode.

Our problem was that we were not getting any audio levels when we were in 30p mode (with a fresh disk) having the camera set to 4 channel audio.

The only way I was able to get audio levels to apper in 30p mode was to change the setting to 2 channel audio.

Does the 4 channel audio record function only work in 60i?

[Greg Boston]

Originally Posted by Matt Trecartin

yeah sorry, I wasn't very clear.

We can of course record either 2 or 4 channels of audio in 60i mode.

Our problem was that we were not getting any audio levels when we were in 30p mode (with a fresh disk) having the camera set to 4 channel audio.

The only way I was able to get audio levels to apper in 30p mode was to change the setting to 2 channel audio.

Does the 4 channel audio record function only work in 60i?

There are also some switches in the upper left corner of the control panel for audio monitoring. Perhaps your situation was related to the setting of those switches. Look at them and you'll see what I mean. Not having been there, and seen exactly what happened, I'm having a hard time visualizing the problem you're describing.

I'll try to duplicate what you are talking about. Just to be clear, were you wanting the front mic as your audio source when all this was happening?

-gb-

[Thierry Humeau]

Originally Posted by Greg Boston

Something doesn't sound right. I can't tell exactly from your description exactly what was happening.


You should be able to choose 2ch or 4ch in 60i. Just keep in mind that whatever you choose, when you put a fresh disc in the camera, the disc will get formatted to that setting. You can't change the number of audio channels in the middle of a disc. You have to re-format, or use a fresh disc. Same goes for 23.98.

.......snip
-gb-

Actually, formatting does not set the disc to any particular recording mode yet. It is only after you record the first clip on the disc that the disc format is set.

Thierry.

[Thierry Humeau]

Originally Posted by Matt Trecartin

yeah sorry, I wasn't very clear.

We can of course record either 2 or 4 channels of audio in 60i mode.

Our problem was that we were not getting any audio levels when we were in 30p mode (with a fresh disk) having the camera set to 4 channel audio.

The only way I was able to get audio levels to apper in 30p mode was to change the setting to 2 channel audio.

Does the 4 channel audio record function only work in 60i?

When you say "getting audio levels to appear...", are you talking about the camera's LCD audio meters? Did you make sure that each of your AUDIO IN switches was set to a valid incoming audio channel? Also, you may have mistaken your audio input CH setting with the one for i.Link audio out which also let you choose between 2 and 4 Channels.

Thierry.

[Uli Mors]

I dont own a XDCAM HD (yet), but manual says

(SPECS)

AUDIO:
MPEG HD: 16/24 Bits, 48 KHz, 4/2 channels
DVCAM: 16 bits 48Khz 4 Channels


It looks like you have to switch the res to 16bit in the menu to have access to 4 channels instead 24bits/2 channel.

Have a try.

Regards

ULI

[Matt Trecartin]

Originally Posted by Uli Mors

I dont own a XDCAM HD (yet), but manual says

(SPECS)

AUDIO:
MPEG HD: 16/24 Bits, 48 KHz, 4/2 channels
DVCAM: 16 bits 48Khz 4 Channels


It looks like you have to switch the res to 16bit in the menu to have access to 4 channels instead 24bits/2 channel.

Have a try.

Regards

ULI

I was just playing with it again. I am in 30p mode and I am now able to switch from 2 channel to 4 channel audio. In the Format Menu I swith from 2 to 4 it flashes 2CHx16 Clip. Telling me that the resolution has changed.

The problem yesterday was that I wasn't getting any audio at all from my front camera mic when I was in 30p mode, until I switched to 60i mode and from 4 the 2 channel. I had all the monitor and input settings right because when I switched it I could see the levels appear in my viewfinder and hear the audio from the monitor.

Anyway, I have audio now in 30p mode so thanks for all the comments. I don't really ever need 4 channels anyway.

BTW, why is there 4 channels of audio and only 3 inputs?

[Nate Weaver]

Originally Posted by Matt Trecartin

BTW, why is there 4 channels of audio and only 3 inputs?

Front input is stereo on a 5pin XLR. You could have a pigtail made that would break out into 2 XLR inputs for your sound guy.

[Matt Trecartin]

Originally Posted by Nate Weaver

Front input is stereo on a 5pin XLR. You could have a pigtail made that would break out into 2 XLR inputs for your sound guy.

Cool, thanks Nate!

[Uli Mors]

If you are ever going to record a music event or a speech thru a soundsystem, 4 channels are a great help.

a) feed the mixing board into one or (stereo) two channels
b) feed the onboard mic or external mics to ch. 3-4 for atmo and applause etc.

In Post I always move the applause track a bit since the audio took some meters to travel - so its out of phase or even delayed.

At the moment I realize that with an EDIROL R4 4track recorder - when changing to xdcam hd I probably will use the f350 for that.

Regards

ULI

[Matt Trecartin]

I was talking to my Online facility today and they said 24bit audio is a waste of space since they work in 16bit anyway.

Looks like I will be running 4 channel all the time.

[Jeremy Spruston]

Hey Nate, any idea where you get one of those made? The ability to run three wireless mics off the camera would be great. I guess that would mean replacing the XDCAM HDs standard onboard microphone as well with something that plugs into a three pin XLR (mono) connection?

[Greg Boston]

Originally Posted by Matt Trecartin

I was talking to my Online facility today and they said 24bit audio is a waste of space since they work in 16bit anyway.

Looks like I will be running 4 channel all the time.

I was told by Sony that there is no 24 bit audio on the XDCAM HD camera. The SD cameras have 24 bit audio capability. The manual has a typo I believe cause I remember looking all over the menus for the place to change the bit depth setting while in 2 channel mode. I'm going to make an effort to verify this once and for all because even the new version of the manual still says 24 bit audio is possible in 2 channel MPEG HD mode. As you can see from your error message below, you are recording 2 channel 16 bit audio so no need to keep it in 4 channel.

Originally Posted by Matt Trecartin

In the Format Menu I swith from 2 to 4 it flashes 2CHx16 Clip

This is indicating that your disc already has clips recorded in 2 channel mode and you can't switch to 4 channel unless you erase all the clips off the disc. As Thierry says, the format is determined by the first clip to be recorded not by the formatting process itself.

-gb-

[Matt Trecartin]

OH, so I can't switch back and forth between 2 and 4 channel on the same disk. Gotcha.


It would be intetresting to know if this 24b myth is just a typo or some creative marketing...